As an expert sommelier and brewer, I have had the pleasure of tasting and making various types of cider, including hard cider. When it comes to the taste of hard cider, it is not necessarily supposed to be sour, but it can develop sour flavors under certain circumstances.
Hard cider is typically made by fermenting apple juice, which naturally contains sugars, with yeast. During fermentation, the yeast consumes the sugars and produces alcohol, carbon dioxide, and other compounds. The flavor profile of the final cider can vary depending on various factors such as the type of apples used, the yeast strain, fermentation temperature, and the duration of fermentation.
In general, hard cider is expected to have a balance of sweetness and acidity, with hints of apple flavors. It should not taste overly sour, like vinegar. However, there are instances where hard cider can develop a sour taste, similar to vinegar. This usually occurs when the cider undergoes a secondary fermentation process, also known as turning or going off.
When hard cider starts to turn, it will become darker in color and may start to froth. This is a sign of the cider undergoing fermentation once again, but this time the process is not desired. This secondary fermentation can happen due to the presence of wild yeast or bacteria in the cider, which can cause the production of acetic acid, leading to the sour taste.
It is important to note that the sourness in turned hard cider is not harmful. It simply means that the cider has started to ferment further and has developed some off-flavors. Some people may enjoy the complex and tangy flavors that come with turned cider, while others may prefer the original taste. It ultimately comes down to personal preference.
To prevent hard cider from turning sour, proper fermentation and storage techniques are crucial. Ensuring that the fermentation process is complete before bottling and storing the cider in a cool and stable environment can help minimize the chances of secondary fermentation. Additionally, using sanitized equipment and properly handling the apples during pressing can help prevent the introduction of unwanted microorganisms.
In my own experience as a brewer, I have encountered instances where hard cider has turned sour. This can happen if there is a contamination in the equipment, such as not properly sanitizing the fermentation vessel or using tainted apples. It can also occur if the cider is exposed to oxygen for an extended period, allowing the growth of acetic acid bacteria.
Hard cider is not supposed to be sour, but it can develop sour flavors if it undergoes a secondary fermentation process. When hard cider turns, it becomes darker, froths, and tastes more sour like vinegar. However, this sourness is not harmful and can be enjoyed by some individuals. Preventing the cider from turning sour involves proper fermentation and storage techniques, as well as maintaining cleanliness throughout the cider-making process.